SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b0bc6cb08e946f6314cfbaf052ba0b78abae23abb065572d77e58deac71d230' 
  AND token = 'AdcICFGmsVHv4nGOC1vqYrdUEnVrvb81NpMt8mSmPdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}